1. Field of the Invention
The present invention relates to a high-frequency signal transmission line, an electronic device and a manufacturing method of the high-frequency signal transmission line, and more particularly to a high-frequency signal transmission line preferably for use in high-frequency signal transmission, an electronic device and a manufacturing method of the high-frequency signal transmission line.
2. Description of the Related Art
As a conventional high-frequency signal transmission line, for example, a high-frequency signal line disclosed in WO 2012/073591 is known.
The high-frequency signal line disclosed in WO 2012/073591 includes a dielectric body, a signal line and two ground conductors. The dielectric body is a laminate of dielectric sheets. The signal line is located in the dielectric body. The two ground conductors are located in the dielectric body so as to sandwich the signal line in the direction of lamination. Accordingly, the signal line and the ground conductors form a stripline structure.
The high-frequency signal line disclosed in WO 2012/073591 has a problem of having a great insertion loss. Specifically, the signal line has a rectangular or substantially rectangular cross-sectional shape. Therefore, lines of electric force generated between the signal line and the ground conductors concentrate on the edges of the signal line because of an edge effect. Accordingly, a current flows not entirely in the signal line but intensively in narrow areas near the edges of the signal line. This results in a great insertion loss.